This invention relates to electronic parcel registers, hereinafter referred to as registers, and is directed to a register of the type having a keyboard for the entry of information to be printed, a display for displaying such information, an electronic accounting unit, and a printing mechanism. In a register, provision must be made for the printing of a postage tape as well as a COD tape, both of which are attached to a parcel to be shipped by a parcel service company. Although the word postage is generally defined as a fee for postal services, the word "postage" as used throughout this specification includes fees charged by private carriers for the delivery of packages or parcel. The register, which serves as an input unit, is secured to and cooperates with a base to print and disperse tapes which are to be affixed to a parcel. The COD tapes indicate that the parcel is to be sent COD and shows the amount that is charged for a parcel having been sent COD. Obviously, the postage tape is stamped with the amount that is required to ship a parcel the required distance in accordance with the weight of the parcel. Such tapes are also stamped with a parcel identification number (PIN) to indicate the number of parcels for which tapes have been printed. Use of such PIN provides a means of security so as to detect unauthorized use of the register. When both postage tapes and COD tapes are to be applied to a parcel, it is required that the same PIN be printed on both tapes otherwise there would be no integrity with regard to the system for accounting for the number of parcels that are stamped by the register. The amount printed on the COD tape is usually a fixed amount but it has been necessary in prior registers to input the COD amount on each occasion. It obviously would be desirable to print a COD tape with a fixed amount without need of constant inputting, but being able to change the COD amount when required.
In prior devices of the general category, including electronic postal meter operation, it has been found desirable to employ one or more microprocessors to control various functions and operations. For security reasons, all data relating to accounting should be maintained separately from other data relating to nonsecure information. By separate maintenance of secure data it is therefore possible to improve security while employing concepts of distributed processing by the use of multiple processors.
The use of multiple processing in a secure environment places stringent requirements on error rate in interprocessor communications, which requirements must be satisfied in order to have successful operation. It is further desired to provide a system of this type which can easily subrogate its control authority to an external unit, thereby allowing substantially one hundred percent control of register function to be transferred to an external device, without any change in system hardware. This subrogation also allows the external device to control or change register configurations internal to the register that are not normally allowed in normal register operation.